Re: [Qemu-devel] [PATCH v1] kvm/x86: Hyper-V tsc page setup

[Denis V. Lunev]

On 01/20/2016 05:05 PM, Paolo Bonzini wrote:
> On 19/01/2016 08:48, Denis V. Lunev wrote:
> > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > > index 6877b4d7e..93c9e25 100644
> > > --- a/include/linux/kvm_host.h
> > > +++ b/include/linux/kvm_host.h
> > > @@ -145,6 +145,7 @@ static inline bool is_error_page(struct page *page)
> > >    #define KVM_REQ_HV_RESET          29
> > >    #define KVM_REQ_HV_EXIT           30
> > >    #define KVM_REQ_HV_STIMER         31
> > > +#define KVM_REQ_HV_TSC_PAGE       32
> > >      #define KVM_REQ_MAX               64
> > >    
> > ping
> Applied with this change:
>
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index d7716c6e2752..047c275717d3 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -842,7 +842,7 @@ int kvm_hv_setup_tsc_page(struct kvm_vcpu *vcpu)
>                    tsc_khz, tsc, tsc_scale, tsc_offset);
>   
>   	tsc_ref.tsc_sequence++;
> -       if (tsc_ref.tsc_sequence == 0)
> +       if (tsc_ref.tsc_sequence == 0xFFFFFFFF tsc_ref.tsc_sequence == 0)
>                 tsc_ref.tsc_sequence = 1;
>   
>   	tsc_ref.tsc_scale = tsc_scale;
>
> and renumbering KVM_REQ_HV_TSC_PAGE from 32 to 31.
>
> Paolo
the latter does not seem to be correct to me.
MS spec has bug, see this thread:
   https://lkml.org/lkml/2015/11/2/655
and the change was Acked-by: K.Y.

Den